feat: Handle error when downloading and writing torrent file

Signed-off-by: prajwalch <prajwal.chapagain58@gmail.com>

app/src/main/kotlin/com/prajwalch/torrentsearch/torrentfiledownloader/TorrentFileDownloader.kt

@@ -5,11 +5,13 @@ import com.prajwalch.torrentsearch.data.repository.TorrentsRepository
 
 import dagger.hilt.android.scopes.ViewModelScoped
 
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.receiveAsFlow
 
+import java.io.IOException
 import java.io.OutputStream
 import javax.inject.Inject
 
@@ -24,7 +26,11 @@ sealed interface TorrentFileDownloadState {
 sealed interface TorrentFileDownloadEvent {
     data class ReadyToWrite(val fileName: String) : TorrentFileDownloadEvent
 
+    data class DownloadFailed(val message: String?) : TorrentFileDownloadEvent
+
     data object WriteSucceed : TorrentFileDownloadEvent
+
+    data class WriteFailed(val message: String?) : TorrentFileDownloadEvent
 }
 
 @ViewModelScoped
@@ -41,22 +47,33 @@ class TorrentFileDownloader @Inject constructor(
 
     suspend fun downloadFile(url: String, fileName: String) {
         reset()
-
         _state.value = TorrentFileDownloadState.Downloading
-        pendingFileId = torrentsRepository.downloadTorrentFile(url = url)
 
-        _events.send(TorrentFileDownloadEvent.ReadyToWrite(fileName))
-        _state.value = TorrentFileDownloadState.Empty
+        try {
+            pendingFileId = torrentsRepository.downloadTorrentFile(url)
+            _events.send(TorrentFileDownloadEvent.ReadyToWrite(fileName))
+        } catch (e: CancellationException) {
+            // Never catch this.
+            throw e
+        } catch (e: Throwable) {
+            _events.send(TorrentFileDownloadEvent.DownloadFailed(e.message))
+        } finally {
+            _state.value = TorrentFileDownloadState.Empty
+        }
     }
 
     suspend fun writeFile(outputStream: OutputStream) {
         val pendingFileId = pendingFileId ?: return
-
         _state.value = TorrentFileDownloadState.Writing
-        torrentsRepository.writeTorrentFile(fileId = pendingFileId, outputStream = outputStream)
 
-        _events.send(TorrentFileDownloadEvent.WriteSucceed)
-        reset()
+        try {
+            torrentsRepository.writeTorrentFile(pendingFileId, outputStream)
+            _events.send(TorrentFileDownloadEvent.WriteSucceed)
+        } catch (e: IOException) {
+            _events.send(TorrentFileDownloadEvent.WriteFailed(e.message))
+        } finally {
+            reset()
+        }
     }
 
     fun reset() {

app/src/main/kotlin/com/prajwalch/torrentsearch/ui/TorrentFileDownloadEffect.kt

@@ -34,8 +34,10 @@ fun TorrentFileDownloadEffect(
     }
 
     val fileDownloadingMessage = stringResource(R.string.torrent_file_downloading_message)
+    val fileDownloadError = stringResource(R.string.torrent_file_download_error)
     val fileSavingMessage = stringResource(R.string.torrent_file_saving_message)
     val fileSavedMessage = stringResource(R.string.torrent_file_saved_message)
+    val fileSaveError = stringResource(R.string.torrent_file_save_error)
 
     LaunchedEffect(Unit) {
         events.collect { event ->
@@ -44,9 +46,25 @@ fun TorrentFileDownloadEffect(
                     createTorrentFileLauncher.launch(event.fileName)
                 }
 
+                is TorrentFileDownloadEvent.DownloadFailed -> {
+                    val message = event.message
+                        ?.let { "$fileDownloadError: $it" }
+                        ?: fileDownloadError
+
+                    snackbarHostState.showSnackbar(message = message)
+                }
+
                 TorrentFileDownloadEvent.WriteSucceed -> {
                     snackbarHostState.showSnackbar(message = fileSavedMessage)
                 }
+
+                is TorrentFileDownloadEvent.WriteFailed -> {
+                    val message = event.message
+                        ?.let { "$fileSaveError: $it" }
+                        ?: fileSaveError
+
+                    snackbarHostState.showSnackbar(message = message)
+                }
             }
         }
     }

app/src/main/kotlin/com/prajwalch/torrentsearch/util/TorrentUtils.kt

@@ -0,0 +1,4 @@
+package com.prajwalch.torrentsearch.util
+
+object TorrentUtils {
+}

app/src/main/res/values/strings.xml

@@ -39,8 +39,10 @@
     <string name="torznab_conn_check_result_unexpected_error">Unexpected error</string>
 
     <string name="torrent_file_downloading_message">Downloading torrent file…</string>
+    <string name="torrent_file_download_error">Download failed</string>
     <string name="torrent_file_saving_message">Saving torrent file…</string>
     <string name="torrent_file_saved_message">Torrent file saved</string>
+    <string name="torrent_file_save_error">Torrent file save failed</string>
 
     <string name="crash_screen_title">Oops!</string>
     <string name="crash_screen_subtitle">